Acoustic Emission Characteristics of Rock Fragmented by TBM Cutter

To study acoustic emission(AE) characteristics of rock fragmentationed by tunnel boring machine (TBM) cutter, a mechanical rock fragmentation experimental platform of Beijing University of Technology was used, and the acoustic emission system was employed for real-time monitoring.In the experiment, the disc cutter with a constant cross section was used and the test granite rock sample was taken from Beishan, Gansu Province of China. A series of tests with different penetrations were conducted and AE signal was collected during the process. AE energy and AE energy rate were analyzed, and AE location calculated with Geiger algorithm was demonstrated after signal de-noising using wavelet transform. Results show that AE energy rate has the similar change trend with the normal force. AE energy increases with the growth of penetration, and can be applied to representation of the energy consumed in rock fragmentation. An approximate description of damage zone that was obtained by AE location shows the whole process of crack accumulation and propagation during rock fragmentation.